Shell Script Cheat Sheet

Basic Commands

• echo "Hello World": Print text to the console.
• read varname: Read input from the user and store it in varname.
• export VARNAME=value: Set environment variable VARNAME to value.
• pwd: Print the current working directory.
• cd directory: Change the current directory to directory.
• ls: List directory contents.
• cp source destination: Copy files from source to destination.
• mv source destination: Move files from source to destination.
• rm file: Remove a file.

Variables

• VAR="value": Define a variable.
• $VAR: Access the value of a variable.
• ${VAR}: Also used to access a variable, useful in complex strings.

Conditional Statements

If Statement

if [ condition ]; then
    # commands
elif [ condition ]; then
    # commands
else
    # commands
fi

Case Statement

case $variable in
    pattern1)
        # commands
        ;;
    pattern2)
        # commands
        ;;
    *)
        # default commands
        ;;
esac

Loops

For Loop

for var in list; do
    # commands
done

While Loop

while [ condition ]; do
    # commands
done

Functions

function_name () {
    # commands
}

File Testing

• -f file: True if the file exists and is a regular file.
• -d directory: True if the directory exists.
• -e path: True if the path exists.
• -r file: True if the file is readable.
• -w file: True if the file is writable.
• -x file: True if the file is executable.

Debugging

• set -x: Enable debugging.
• set +x: Disable debugging.